The present invention relates to a syringe with an encoding for use with a metering device having a sensing device for sensing the encoding, and a syringe system comprising several syringes having different encodings. Further, the present invention relates to a metering device having a sensing device for sensing an encoding for use with a syringe having an encoding. Further, the present invention relates to a metering system comprising a syringe having an encoding, and a metering device having a sensing device for sensing the encoding. Finally, the present invention relates to a method for operating a metering system comprising a syringe with an encoding, and a metering device with a sensing device for sensing the encoding.
Syringes and metering systems comprising metering devices serve for metering liquids, and are used in biological, chemical and medical laboratories in particular. Metering devices configured as a dispenser permit the stepwise delivery of a liquid from a syringe. The metering amount per delivery step can be adjustable. A dispenser with metering amount adjustment is known from the document DE 29 26 691 C2, the entire contents of which is incorporated herein by reference.
Syringes of different sizes are often offered for metering devices. These have mostly different cross section dimensions. When going over to another syringe size, the set metering amount does no more coincide with the real metering amount. Therefore, metering devices have become known where the syringe has an encoding which is read out by a sensing device of the metering device. An analysing device determines the really inserted syringe size and the really set metering amount, which can be indicated by a display device.
A metering system of the mentioned kind is known from the documents EP 0 657 216 B1, the entire contents of which is incorporated herein by reference, and U.S. Pat. No. 5,620,661A, the entire contents of which is incorporated herein by reference. In these repeater pipettes, the repeater pipette has a seat for a fastening portion of a syringe in a pipette casing, and in an accommodation body a piston seat for the syringe piston of the syringe. In addition, there are fastening devices for reversibly fixing fastening portion and syringe piston in their seats, and piston adjustment devices for moving the accommodation body in the pipette casing. The syringe has an information carrier with information about the syringe and/or the condition thereof, and the repeater pipette has a sensing device for the information on the information carrier. The fastening portion and the syringe piston area adapted to be axially moved into their fastening positions in the repeater pipette via axial openings of their seats, wherein the information carrier arrives in a sensing position with respect to the sensing device. The syringe flange has an annular collar with at least one axially directed sensing surface with an axial position as the information carrier, the syringe being insertable into the repeater pipette in different rotational positions. The sensing device is realised in ring shape, with sensors distributed over the circumference. The sensors have elastically resilient naps which project from a front side of the sensing device facing the axial openings. Preferably, there is an analysing device for the information read out by the sensing device, and a display device for the set metering amount. For reproducible alignment of the syringe with its information carrier to the sensing device, there are alignment noses on the fastening portion of the syringe, and guide grooves in the seat for the fastening portion.
In a practical embodiment, the syringe has seven sensing surfaces on the syringe flange, and the annular sensing device of the repeater pipette has seven sensors that are uniformly distributed over the circumference. Further, the syringe is provided with seven alignment noses which are uniformly distributed over the circumference and are guided on axially directed bridges on a lateral limiting wall of the seat of the repeater pipette, in order to align the sensing surfaces with the sensors.
The alignment noses are each chamfered at the topside, in order to guide the bridges into the noses between the alignment noses when these are not accurately aligned with the bridges. Each alignment nose is disposed between two neighbouring sensing surfaces. The syringes are marketed under the product name “Combitips® Plus, and the pipettes under the product name “Multipipette® Plus” by Eppendorf AG.
The repeater pipette system permits a user to adopt the syringe size according to the practical requirements, and to adjust the metering amount without sumptuous conversion calculations. Instead of the syringe size, the information may also contain other specific data of the syringe and/or of the condition thereof, for instance the degree of purity or a filling substance of the syringe, which is automatically taken into account by the repeater pipette.
In the known repeater pipette system, a malfunction of one or several sensors of the sensing device, wrong insertion of the syringe into the repeater pipette or insertion of a not suitable syringe can lead to erroneous detection and display of the metering amount that is set. As a consequence, erroneous metering may occur.
Further metering systems with syringes having an encoding and sensing devices of the metering device for sensing the encoding are known from the documents EP 0 691 158 B1, the entire contents of which is incorporated herein by reference, and EP 0 951 306 B1, the entire contents of which is incorporated herein by reference. According to EP 0 691 158 B1, the encoding is disposed on the piston of the syringe and the pipetting apparatus has a device for automatic identification of the encoding on the piston. According to EP 0 951 306 B1, the syringe has a series of deepenings on the attachment flanges, which are read out by sensor switches of the metering device when the deepenings move along the sensor switches upon rotation of the syringe. Even in these syringes, display errors may occur due to the mentioned reasons.
Starting from this, the present invention is based on the task to provide a syringe for use with a metering device, a syringe system comprising several syringes for use with a metering device, a metering device for the use with a syringe, a metering system comprising a syringe and a metering device, and a method for operating a metering system, which diminish the risk of erroneous metering. Moreover, there must be the possibility to realise the syringes such that they comply with the practical embodiments of the metering device according to EP 0 657 216 B1.
The syringe of the present invention with a syringe cylinder and a syringe piston for use with a metering device for metering liquids in the laboratory, with a seat for the syringe cylinder and an axially displaceable piston seat for the syringe piston comprises:                an encoding on the upper edge of the syringe cylinder with encoding elements in the form of protrusions and deepenings at seven encoding positions uniformly distributed over the circumferential direction in an arrangement that is characteristic for the type of the syringe,        checking elements in the form of further protrusions and further deepenings at seven checking positions, each of them being disposed between two encoding positions on the upper edge of the syringe cylinder,        wherein the encoding elements and the checking elements have six protrusions in total, and        a guiding structure on the circumference of the syringe cylinder, which has a certain position with respect to the encoding elements and the checking elements in order to align the syringe on a further guiding structure with each encoding element and with each checking element to a sensing element, said further guiding structure being disposed in the seat of the metering device and having a certain position with respect to an annular sensing device of the metering device for sensing the encoding by sensing elements that are uniformly distributed across the circumference.        
In addition to the encoding with encoding elements in the form of protrusions and deepenings, the syringe of the present invention has checking elements on the upper edge of the syringe cylinder, in the form of further protrusions and further deepenings. The encoding elements are disposed at seven encoding positions that are uniformly distributed in the circumferential direction, and the checking elements are disposed at seven checking positions, each checking position being located between two encoding positions. The protrusions and deepenings stand out differently far away from the syringe cylinder in the axial direction of the syringe, i.e. in the direction of the syringe piston's displacement in the syringe cylinder. The encoding elements and the checking elements have six protrusions in total. In principle, the syringe can be axially inserted into the seats of a metering device for the upper area of the syringe cylinder and of the syringe piston in any arbitrary rotational position. A guiding structure on the circumference of the syringe cylinder has a certain position with respect to the encoding elements and the checking elements. Through this, it is ensured that when inserting the syringe into the seats, the guiding structure is guided by a further guiding structure in the seat of a metering device having a certain position with respect to an annular sensing device of the metering device, such that each encoding element and each checking element is aligned with an individual one of the sensing elements. The sensing elements are sensors which can determine whether a protrusion is directed towards the sensing element. For this purpose, sensors can be used in particular which are actuated by a protrusion and are not actuated by an depression, or sensors which are actuated by a protrusion in a way which is different from that of an depression. The syringe permits to check whether the encoding is sensed without errors. Only when the sensing device senses six protrusions in total, error-free sensing of the encoding is possible. If less or more than six protrusions are sensed, there is an error which might be due, for instance, to incorrect insertion of the syringe into the metering device, a malfunction of the sensing device or the use of a not suited syringe. Erroneous metering can be avoided by detecting an error.
In that the encoding elements and the checking elements have six protrusions in total, sensing the encoding elements and the checking elements is accompanied by only small energy consumption and small load of the sensing elements. Moreover, the force for the insertion of the syringe and the metering device is small because only a few sensing elements must be actuated.
Like the already known syringes Combitips® Plus of Eppendorf AG, the syringe of the present invention has an encoding with encoding elements at seven encoding positions. Thus, it is possible to produce syringes of the present invention with the same encodings as the known syringes Combitips® Plus. But in difference to the known syringes, the additional checking elements of the syringes of the present invention permit error detection in the process of sensing the encoding. For this purpose, the syringes of the present invention are inserted into metering devices having a sensing device, which senses the encoding elements and the checking elements. Syringes of the present invention which have the same encoding and guiding structures associated to the encoding like the Combitips® Plus can also be put into conventional metering devices Multipette® Plus of Eppendorf AG, whose sensing device senses only the encoding elements. Thus, the conventional metering device Multipette® Plus of Eppendorf AG can also sense the encoding of the syringes of the present invention, and display the metering volume that is set. However, error detection due to sensing of encoding elements and checking elements cannot be performed in this possible utilisation.
An additional surprising advantage of the syringe of the present invention is that the checking elements can be used as additional encoding elements. Namely, the checking elements can be disposed on the upper edge of the syringe cylinder at different positions with respect to the encoding elements. This permits additional encoding of the syringe. For instance, different syringe volumes can be encoded like in the known syringes Combitips® Plus. The checking elements may encode additional properties of the syringes. In particular, it is possible to differentiate syringes which have the same filling volume but which are distinct from each other by special properties. For instance, these properties can be the material, the filling condition, the purity condition of the syringes or a medium that is filled into them.
The protrusions and/or deepenings have preferably smooth and/or uninterrupted surfaces. But the present invention incorporates also syringes with protrusions and deepenings which are formed by rough and/or interrupted surfaces, provided that the position of their body-remote ends can be palpitated by a sensing device. For instance, protrusions and/or deepenings are incorporated into the invention which have a number of parallel grooves, whose width is smaller than the diameter of the palpitating head of a sensing device, so that the sensing device cannot intrude into the grooves.
According to an advantageous embodiment of the syringe, the encoding elements have at most five protrusions and the checking elements at least one protrusion. With this embodiment, all the encodings of the conventional Combitips® Plus can be implemented.
According to a further embodiment, the syringe has one of the filling volumes and protrusions indicated below only at the encoding positions 1 to 7 associated to the respective filling volume, which are disposed clockwise in succession in a top view towards the upper edge of the syringe cylinder, wherein a checking position having a further protrusion exists between at least two encoding positions:                0.1 ml filling volume with protrusions at encoding positions 4, 6 and 7,        0.2 ml filling volume with protrusions at encoding positions 3, 6 and 7,        0.5 ml filling volume with protrusions at encoding positions 2, 6 and 7,        1.0 ml filling volume with protrusions at encoding positions 2, 5 and 7,        2.5 ml filling volume with protrusions at encoding positions 2, 4, 5, 6 and 7,        5.0 ml filling volume with protrusions at encoding positions 2, 3, 5, 6 and 7,        10 ml filling volume with protrusions at encoding positions 3, 4, 5, 6 and 7,        25 ml filling volume with a protrusion at encoding position 7,        50 ml filling volume with protrusions at encoding positions 5, 6 and 7.        
The above-mentioned variants of the syringe have the encodings of the known syringes Combitips® Plus. In the above encodings, the distribution of the protrusions to the different encoding positions is in each case unambiguously associated to a syringe with a certain filling volume, so that the associated filling volume can be unambiguously assigned by way of the respective distribution of the protrusions to different encoding positions, without having to know the position of a special encoding position (e.g. of encoding position 1). Thus, the syringes can be inserted into the metering device in all the arbitrary orientations which are permitted by the guiding structures.
According to a further embodiment, the syringe has one of the filling volumes and protrusions indicated below only at the checking positions 1 to 7 associated to the respective filling volume, which are disposed clockwise in succession in a top view towards the upper edge of the syringe cylinder:                0.1 ml filling volume with protrusions at checking positions 1, 2 and 4,        0.2 ml filling volume with protrusions at checking positions 1, 3 and 4,        0.5 ml filling volume with protrusions at checking positions 1, 3 and 4,        1.0 ml filling volume with protrusions at checking positions 1, 3 and 5,        2.5 ml filling volume with a protrusion on the checking position 1,        5.0 ml filling volume with a protrusion on the checking position 1,        10 ml filling volume with a protrusion on the checking position 1,        25 ml filling volume with protrusions at checking positions 1, 2, 3, 4 and 5,        50 ml filling volume with protrusions at checking positions 1, 2 and 3.        
These variants have the encodings of the known Combitips® Plus and checking elements with protrusions at specific positions, wherein the encoding elements and the checking elements have six protrusions in total. In principle, the checking elements with protrusions can also be disposed at other checking positions, provided the total number of protrusions is not changed. Through this, differentiations of syringes having the same metering volume are possible. Even in these variants, the distribution of the protrusions to different encoding positions and checking positions is in each case unambiguously associated to a syringe with a certain filling volume.
According to a further embodiment, the guiding structure has guiding elements which are disposed at positions on the circumference of the syringe cylinder whose mutual distance corresponds to one seventh or several times one seventh of the perimeter of the syringe cylinder, in order to align the syringe on a further guiding structure of a metering device with the encoding elements to sensing elements for encoding elements, and with the checking elements to sensing elements for checking elements. According to a preferred embodiment, seven guiding elements are disposed on the circumference of the syringe cylinder, wherein the mutual distance of neighbouring guiding elements corresponds in each case to one seventh of the perimeter of the syringe cylinder. By the alignment of the encoding elements to associated sensing elements for encoding elements of the metering device, the analysis of the encoding is facilitated. Moreover, by the alignment of the checking elements to sensing elements for checking elements, the potential of supplementary encodings is enlarged with the aid of the checking elements. Further, it is achieved by this that when syringes of the present invention are put into conventional pipettes Multipette® Plus, the encoding elements are aligned with the sensing elements of the sensing device, so that the set metering volume is displayed.
According to one embodiment, the guiding elements are disposed on the circumference of the syringe cylinder or on the circumference of a fastening portion of the syringe cylinder. According to another embodiment, the guiding elements are aligning noses between which there are gaps. The aligning noses serve for introducing axial ribs in a seat of the metering device for syringes into the gaps between the aligning noses.
According to a further embodiment, the alignment noses are each one disposed in a radial direction with respect to the centre axis of the syringe cylinder next to the checking elements, and the gaps are disposed in the radial direction next to the encoding elements.
According to another embodiment, the guiding structures are configured such that the encoding elements and the checking elements are associated to arbitrary sensing elements when the syringe is put into the metering device. By analysing the actuated sensing elements, the analysing device of the metering device of the present invention can determine the encoding through the encoding elements, and as the case may be a supplementary encoding by the checking elements, provided that each syringe is provided with a characteristic pattern of encoding elements and checking elements.
The syringe is preferably made of a plastic material. The syringe cylinder and the syringe piston can be made of the same or of different plastics. According to a further embodiment, the syringe cylinder is made of polypropylene or polyethylene or cyclic olefinic (CO) polymer, and/or the syringe piston is made of polyethylene or polypropylene. Preferably, the syringe cylinder consists of polypropylene, and the syringe piston of polyethylene.
The syringe system of the present invention permits the user to select certain syringes of the system depending on the intended utilisation, and to use them with the aid of a metering device. The selected syringes are characterised by their encoding. The encodings can be read out by way of a metering device of the present invention, wherein a contingency check is performed with the aid of the checking elements.
The metering device of the present invention for use with a syringe having a syringe piston and a syringe cylinder for metering liquids in the laboratory comprises                a seat for the upper end of the syringe cylinder,        an accommodation body with a piston seat for the upper end of the syringe piston,        holding devices for detachably holding the upper end of the syringe cylinder and the upper end of the syringe piston in their seats,        piston adjustment devices for moving the accommodation body relative to the seat,        an annular sensing device, disposed in the seat and having at least 14 sensing elements that are uniformly distributed over the circumference,        a guiding structure on the circumference of the seat for aligning a further guiding structure on the circumference of the syringe cylinder of a syringe, for aligning seven encoding elements and checking elements, disposed between the encoding elements, to the sensing elements of the sensing device, said encoding elements being uniformly distributed over the upper edge of the syringe cylinder and having the form of protrusions and deepenings in an arrangement of an encoding of the syringe characterising the type of the syringe, the checking elements being in the form of further protrusions and deepenings, and wherein the encoding elements and the checking elements have six protrusions in total, and        an electronic analysing device connected to the sensing elements and being configured such that it states an error-free sensing upon the actuation of exactly six sensing elements, and such that it triggers the metering device into an operating condition only in the case of an error-free sensing, said operating condition depending on the encoding of a syringe determined by analysing the switched sensing elements.        
The metering device has a sensing device, as well as a further guiding structure for aligning a syringe on its guiding structure with the encoding elements and checking elements to one sensing element for each one thereof. The metering device has 14 or 21 or 28 or another manifold of 7 sensing elements, wherein it has at least 14 sensing elements. The sensing elements are directed parallel to the displacement direction of the accommodation body for the upper end of the syringe piston. The metering device has an analysing device, which states an error-free sensing when exactly six sensing elements are actuated. Namely, in this case exactly six protrusions of the syringe are palpated, which indicates error-free sensing. The notice of error-free sensing can occur merely within the device, or can be indicated to the user in a display in addition. In case of an error-free sensing, the analysing device triggers the metering device into an operating condition which depends on the detected encoding of the syringe. The operating condition of the metering device comprises for instance the display or another output of the metering volume that is set. Further, the operating condition can comprise the operation of a drive for the piston adjustment devices with a certain power and/or speed or with a certain power profile and/or speed profile. The power and/or speed can be controlled depending on the material and/or the size of the syringe in particular. Further, the operating condition can comprise a certain advancing path of the drive device for the piston adjustment device. For instance, when syringes of different length are used, the advancing path of the piston adjustment device can be adjusted automatically, or at given metering volume, the advancing path which is necessary for this can be adjusted automatically, depending on the inserted syringe.
The metering device of the present invention is used with syringes of the present invention in order to avoid erroneous metering.
According to one embodiment, the analysing device is configured such that it states an erroneous sensing when another number than six sensing elements are actuated, and triggers the metering device into an error condition. The error condition of the metering device can comprise to display and/or to indicate in another way an error message and/or hints for possible error reasons and/or for the elimination thereof and/or the stop of metering.